In the domain of radio frequency or RF signals such as terrestrial RF signals for analog or digital television channel broadcast systems, which for example comprise a UHF frequency range with a plurality of UHF channels at different frequencies, It is generally known, for example from EP2393226 that such frequency channels of such a frequency range are each received at different power levels. The broadcasting power, transmission distance, signal interference, etc. might considerably vary for different terrestrial broadcasting stations, of which a terrestrial antenna receives such an RF signal. When, for example in television distribution systems, transceiver systems were used that equally amplified the entire frequency range in which the plurality of channels are transmitted, for example the entire UHF frequency range, this would lead to undesired variations in the power level of different frequency channels in the output signal.
In order to solve this problem, transceiver systems are for example known from EP2393226 to individually amplify each frequency channel from the frequency range of the RF signal. EP2393226 discloses a television channel amplification system in which a single analog RF input signal received from an antenna is split by means of a power divider, in such a way that this single analog RF input signal is received by a plurality of transceiver modules. The power divider thus must ensure that this single analog input signal reaches all the transceiver modules. Each such transceiver module comprises an analog filter which selects from this received analog input signal a subset of M channels. It is clear that preferably each transceiver module operates preferably on a different subset of channels from the analog input signal and each transceiver module thus preferably comprises a different filter for the analog RF input signal received by it. According to an embodiment referred to as direct RF digitization, the filtered analog RF signal comprising this particular subset of M channels is then digitized by means of an ADC, amplification is then performed digitally by means of the transceiver modules, and subsequently the amplified signal is again converted to an analog signal by means of a DAC. It is thus clear that each transceiver module thus requires a corresponding ADC and DAC. The outputs of the plurality transceiver modules are then combined in an output signal. A further prior art system is known from EP2728770, which discloses a satellite transponder with a system and a method for processing communication data by analog to digital conversion of the signals, formation of frequency channels and combination of them by a switch with a plurality of stages.
However the system known from EP2393226 presents some problems with respect to scalability and flexibility, especially when coping with a plurality of RF signals. According to the system of EP239226 each RF signal requires a separate transceiver system in which a power splitter splits the RF signal to a plurality of transceiver modules which each comprise a suitably configured filter for the desired selection of a subset of frequency channels. Additionally, as this power splitter and filter operate on the analog RF signal this leads to a complex, inflexible design, and noise inducing components in the analog RF signal path. Further also the system known from EP2728770, in a similar way lacks flexibility, especially when coping with a plurality of RF-signals, as each RF signal requires a separate transceiver system.
Additionally, as pointed out in EP2393226 in paragraph [0032], it is clear for a person skilled in the art that it is very important to optimally adjust the dynamic range of the analog signal comprising the filtered subset of frequency channels to the ADC of each transceiver module, before conversion to the digital domain. As further stated, a person skilled in the art would therefor require, for each transceiver module, a variable gain amplifier in the signal path of the analog signal, which comprises the filtered subset of frequency channels, in order to deliver at all times the same power to the ADC to be included in all the implementations of such a system. It is thus clear that in this way a person skilled in the art, next to the power splitter and filter, would also require such an analog automatic gain control component for each transceiver module.
Therefor there still exists a need for such a system, which is able to handle such terrestrial RF signals with a plurality of frequency channels with large differences in their power level, in a more flexible, simple and efficient way, with a reduced risk for noise induction in the analog RF signal path. There is particularly a need for a more flexible, simple and efficient system for handling a plurality of such RF signals.